Store.h revision 740d490593e0de8732a697c9f77b90ddd463863b 
1//== Store.h - Interface for maps from Locations to Values ------*- C++ -*--==//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10//  This file defined the types Store and StoreManager.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_CLANG_GR_STORE_H
15#define LLVM_CLANG_GR_STORE_H
16
17#include "clang/StaticAnalyzer/Core/PathSensitive/StoreRef.h"
18#include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
19#include "clang/StaticAnalyzer/Core/PathSensitive/SValBuilder.h"
20#include "llvm/ADT/DenseSet.h"
21#include "llvm/ADT/Optional.h"
22
23namespace clang {
24
25class Stmt;
26class Expr;
27class ObjCIvarDecl;
28class StackFrameContext;
29
30namespace ento {
31
32class CallEvent;
33class ProgramState;
34class ProgramStateManager;
35class SubRegionMap;
36
37class StoreManager {
38protected:
39  SValBuilder &svalBuilder;
40  ProgramStateManager &StateMgr;
41
42  /// MRMgr - Manages region objects associated with this StoreManager.
43  MemRegionManager &MRMgr;
44  ASTContext &Ctx;
45
46  StoreManager(ProgramStateManager &stateMgr);
47
48public:
49  virtual ~StoreManager() {}
50
51  /// Return the value bound to specified location in a given state.
52  /// \param[in] store The analysis state.
53  /// \param[in] loc The symbolic memory location.
54  /// \param[in] T An optional type that provides a hint indicating the
55  ///   expected type of the returned value.  This is used if the value is
56  ///   lazily computed.
57  /// \return The value bound to the location \c loc.
58  virtual SVal getBinding(Store store, Loc loc, QualType T = QualType()) = 0;
59
60  /// Return a state with the specified value bound to the given location.
61  /// \param[in] store The analysis state.
62  /// \param[in] loc The symbolic memory location.
63  /// \param[in] val The value to bind to location \c loc.
64  /// \return A pointer to a ProgramState object that contains the same
65  ///   bindings as \c state with the addition of having the value specified
66  ///   by \c val bound to the location given for \c loc.
67  virtual StoreRef Bind(Store store, Loc loc, SVal val) = 0;
68
69  virtual StoreRef BindDefault(Store store, const MemRegion *R, SVal V);
70  virtual StoreRef Remove(Store St, Loc L) = 0;
71
72  /// BindCompoundLiteral - Return the store that has the bindings currently
73  ///  in 'store' plus the bindings for the CompoundLiteral.  'R' is the region
74  ///  for the compound literal and 'BegInit' and 'EndInit' represent an
75  ///  array of initializer values.
76  virtual StoreRef BindCompoundLiteral(Store store,
77                                       const CompoundLiteralExpr *cl,
78                                       const LocationContext *LC, SVal v) = 0;
79
80  /// getInitialStore - Returns the initial "empty" store representing the
81  ///  value bindings upon entry to an analyzed function.
82  virtual StoreRef getInitialStore(const LocationContext *InitLoc) = 0;
83
84  /// getRegionManager - Returns the internal RegionManager object that is
85  ///  used to query and manipulate MemRegion objects.
86  MemRegionManager& getRegionManager() { return MRMgr; }
87
88  /// getSubRegionMap - Returns an opaque map object that clients can query
89  ///  to get the subregions of a given MemRegion object.  It is the
90  //   caller's responsibility to 'delete' the returned map.
91  virtual SubRegionMap *getSubRegionMap(Store store) = 0;
92
93  virtual Loc getLValueVar(const VarDecl *VD, const LocationContext *LC) {
94    return svalBuilder.makeLoc(MRMgr.getVarRegion(VD, LC));
95  }
96
97  Loc getLValueCompoundLiteral(const CompoundLiteralExpr *CL,
98                               const LocationContext *LC) {
99    return loc::MemRegionVal(MRMgr.getCompoundLiteralRegion(CL, LC));
100  }
101
102  virtual SVal getLValueIvar(const ObjCIvarDecl *decl, SVal base);
103
104  virtual SVal getLValueField(const FieldDecl *D, SVal Base) {
105    return getLValueFieldOrIvar(D, Base);
106  }
107
108  virtual SVal getLValueElement(QualType elementType, NonLoc offset, SVal Base);
109
110  // FIXME: This should soon be eliminated altogether; clients should deal with
111  // region extents directly.
112  virtual DefinedOrUnknownSVal getSizeInElements(ProgramStateRef state,
113                                                 const MemRegion *region,
114                                                 QualType EleTy) {
115    return UnknownVal();
116  }
117
118  /// ArrayToPointer - Used by ExprEngine::VistCast to handle implicit
119  ///  conversions between arrays and pointers.
120  virtual SVal ArrayToPointer(Loc Array) = 0;
121
122  /// Evaluates DerivedToBase casts.
123  virtual SVal evalDerivedToBase(SVal derived, QualType basePtrType) = 0;
124
125  /// \brief Evaluates C++ dynamic_cast cast.
126  /// The callback may result in the following 3 scenarios:
127  ///  - Successful cast (ex: derived is subclass of base).
128  ///  - Failed cast (ex: derived is definitely not a subclass of base).
129  ///  - We don't know (base is a symbolic region and we don't have
130  ///    enough info to determine if the cast will succeed at run time).
131  /// The function returns an SVal representing the derived class; it's
132  /// valid only if Failed flag is set to false.
133  virtual SVal evalDynamicCast(SVal base, QualType derivedPtrType,
134                                 bool &Failed) = 0;
135
136  class CastResult {
137    ProgramStateRef state;
138    const MemRegion *region;
139  public:
140    ProgramStateRef getState() const { return state; }
141    const MemRegion* getRegion() const { return region; }
142    CastResult(ProgramStateRef s, const MemRegion* r = 0) : state(s), region(r){}
143  };
144
145  const ElementRegion *GetElementZeroRegion(const MemRegion *R, QualType T);
146
147  /// castRegion - Used by ExprEngine::VisitCast to handle casts from
148  ///  a MemRegion* to a specific location type.  'R' is the region being
149  ///  casted and 'CastToTy' the result type of the cast.
150  const MemRegion *castRegion(const MemRegion *region, QualType CastToTy);
151
152  virtual StoreRef removeDeadBindings(Store store, const StackFrameContext *LCtx,
153                                      SymbolReaper& SymReaper) = 0;
154
155  virtual StoreRef BindDecl(Store store, const VarRegion *VR, SVal initVal) = 0;
156
157  virtual StoreRef BindDeclWithNoInit(Store store, const VarRegion *VR) = 0;
158
159  virtual bool includedInBindings(Store store,
160                                  const MemRegion *region) const = 0;
161
162  /// If the StoreManager supports it, increment the reference count of
163  /// the specified Store object.
164  virtual void incrementReferenceCount(Store store) {}
165
166  /// If the StoreManager supports it, decrement the reference count of
167  /// the specified Store object.  If the reference count hits 0, the memory
168  /// associated with the object is recycled.
169  virtual void decrementReferenceCount(Store store) {}
170
171  typedef llvm::DenseSet<SymbolRef> InvalidatedSymbols;
172  typedef SmallVector<const MemRegion *, 8> InvalidatedRegions;
173
174  /// invalidateRegions - Clears out the specified regions from the store,
175  ///  marking their values as unknown. Depending on the store, this may also
176  ///  invalidate additional regions that may have changed based on accessing
177  ///  the given regions. Optionally, invalidates non-static globals as well.
178  /// \param[in] store The initial store
179  /// \param[in] Regions The regions to invalidate.
180  /// \param[in] E The current statement being evaluated. Used to conjure
181  ///   symbols to mark the values of invalidated regions.
182  /// \param[in] Count The current block count. Used to conjure
183  ///   symbols to mark the values of invalidated regions.
184  /// \param[in,out] IS A set to fill with any symbols that are no longer
185  ///   accessible. Pass \c NULL if this information will not be used.
186  /// \param[in] Call The call expression which will be used to determine which
187  ///   globals should get invalidated.
188  /// \param[in,out] Invalidated A vector to fill with any regions being
189  ///   invalidated. This should include any regions explicitly invalidated
190  ///   even if they do not currently have bindings. Pass \c NULL if this
191  ///   information will not be used.
192  virtual StoreRef invalidateRegions(Store store,
193                                     ArrayRef<const MemRegion *> Regions,
194                                     const Expr *E, unsigned Count,
195                                     const LocationContext *LCtx,
196                                     InvalidatedSymbols &IS,
197                                     const CallEvent *Call,
198                                     InvalidatedRegions *Invalidated) = 0;
199
200  /// enterStackFrame - Let the StoreManager to do something when execution
201  /// engine is about to execute into a callee.
202  virtual StoreRef enterStackFrame(ProgramStateRef state,
203                                   const LocationContext *callerCtx,
204                                   const StackFrameContext *calleeCtx);
205
206  virtual void print(Store store, raw_ostream &Out,
207                     const char* nl, const char *sep) = 0;
208
209  class BindingsHandler {
210  public:
211    virtual ~BindingsHandler();
212    virtual bool HandleBinding(StoreManager& SMgr, Store store,
213                               const MemRegion *region, SVal val) = 0;
214  };
215
216  class FindUniqueBinding :
217  public BindingsHandler {
218    SymbolRef Sym;
219    const MemRegion* Binding;
220    bool First;
221
222  public:
223    FindUniqueBinding(SymbolRef sym) : Sym(sym), Binding(0), First(true) {}
224
225    bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R,
226                       SVal val);
227    operator bool() { return First && Binding; }
228    const MemRegion *getRegion() { return Binding; }
229  };
230
231  /// iterBindings - Iterate over the bindings in the Store.
232  virtual void iterBindings(Store store, BindingsHandler& f) = 0;
233
234protected:
235  const MemRegion *MakeElementRegion(const MemRegion *baseRegion,
236                                     QualType pointeeTy, uint64_t index = 0);
237
238  /// CastRetrievedVal - Used by subclasses of StoreManager to implement
239  ///  implicit casts that arise from loads from regions that are reinterpreted
240  ///  as another region.
241  SVal CastRetrievedVal(SVal val, const TypedValueRegion *region,
242                        QualType castTy, bool performTestOnly = true);
243
244private:
245  SVal getLValueFieldOrIvar(const Decl *decl, SVal base);
246};
247
248
249inline StoreRef::StoreRef(Store store, StoreManager & smgr)
250  : store(store), mgr(smgr) {
251  if (store)
252    mgr.incrementReferenceCount(store);
253}
254
255inline StoreRef::StoreRef(const StoreRef &sr)
256  : store(sr.store), mgr(sr.mgr)
257{
258  if (store)
259    mgr.incrementReferenceCount(store);
260}
261
262inline StoreRef::~StoreRef() {
263  if (store)
264    mgr.decrementReferenceCount(store);
265}
266
267inline StoreRef &StoreRef::operator=(StoreRef const &newStore) {
268  assert(&newStore.mgr == &mgr);
269  if (store != newStore.store) {
270    mgr.incrementReferenceCount(newStore.store);
271    mgr.decrementReferenceCount(store);
272    store = newStore.getStore();
273  }
274  return *this;
275}
276
277// FIXME: Do we still need this?
278/// SubRegionMap - An abstract interface that represents a queryable map
279///  between MemRegion objects and their subregions.
280class SubRegionMap {
281  virtual void anchor();
282public:
283  virtual ~SubRegionMap() {}
284
285  class Visitor {
286    virtual void anchor();
287  public:
288    virtual ~Visitor() {}
289    virtual bool Visit(const MemRegion* Parent, const MemRegion* SubRegion) = 0;
290  };
291
292  virtual bool iterSubRegions(const MemRegion *region, Visitor& V) const = 0;
293};
294
295// FIXME: Do we need to pass ProgramStateManager anymore?
296StoreManager *CreateRegionStoreManager(ProgramStateManager& StMgr);
297StoreManager *CreateFieldsOnlyRegionStoreManager(ProgramStateManager& StMgr);
298
299} // end GR namespace
300
301} // end clang namespace
302
303#endif
304